enum E1 {
  A,
  B,
  C
}

type TE1 = keyof E1;
/**
 拿到的是错误的类型
 type TE1 = "toString" | "toFixed" | "toExponential" | "toPrecision" | "valueOf" | "toLocaleString"
 */

type TE2 = keyof typeof E1;
/**
 拿到的是正确的类型
 type TE2 = "A" | "B" | "C"
 */
